C++ Vectors with Array Elements?

Question

I am doing a project in my class that requires the program to stores teams into a vector. So I would have something like this:

string bballteam; 
vector<string> teamVector;

and then I want the user to input team names. So I can just prompt

cin >> bballTeam; 
teamVector.push_back(bballTeam); 

to store the user input into the vector. However, I would like for the user input to be an array so that I can store players (like a roster). What are some ways I can implement this? I acknowledge that you can't have arrays in a vector.

Answer 1

What you need to know is the following:

If you have many different attributes for one Object, then a struct or class must be used. If you have for example a "Player", then you would put the attributes of "Player" in a struct. Like this:

struct Player {
    std::string firstName{};
    std::string name {};
    unsigned int age{};
    double score{};
};

Here you have one Type with many attributes or properties.

If you need many "Objects" of same Type, then you would store those in an "array" type, like a C-Style array, or an std::array, or, if you need some variable size, a std::vector.

So, again

• Many attributes of different Type will be stored in a struct
• Many obejects with the same Type will be stored in n array.

Of course all these structures or arrays can be nested. You may have an array of struct or a struct containing arrays.

This depends on how you want to abstract the reality. It is about "relations".

For the input: Objects of the same Type are entered in "loops", e.g. a for or a while loop.

Object attributes of different Type will be entered one after the other.

---

If you have a struct or class and want to enter all its attributes with a simple extraction (>>) operation, then you will observe that the existing extract operator >> does not know, how to work with your Type. That, because you defined a new Type, for example "Player". So we need to tell the compiler how to "Get" the data. And for that, we need to define the input functionality for the new Type. This is done with so called operator overloading. Sorry, you need to read about that. But, it is simple for input and for output. Within a struct you can normally use the following function signature:

struct Player {
    std::string firstName{};
    std::string name {};
    unsigned int age{};
    double score{};

    // Extraction (input)
    friend std::istream& operator >> (std::istream& is, Player& p);

    // Insertion (output)
    friend std::ostream& operator << (std::ostream& os, const Player& p);
};

You need to program the details of these functions.

So, next, the Team. Here you need many objects of the same Type, so many "Players".

You could write std::vector<Player> team{}; to define a team having many players.

And a complete example for the stuff learned so far:

#include <iostream>
#include <string>
#include <vector>
#include <iomanip>

struct Player {
    std::string firstName{};
    std::string name{};
    unsigned int age{};
    double score{};

    // Extraction (input)
    friend std::istream& operator >> (std::istream& is, Player& p) {
        std::getline(is >> std::ws, p.firstName);
        std::getline(is, p.name);
        return is >> p.age >> p.score;
    }
    // Insertion (output)
    friend std::ostream& operator << (std::ostream& os, const Player& p) {
        return os << p.firstName << ' ' << p.name << ' ' << p.age << ' ' << p.score;
    }
};

int main() {
    // Define the team
    std::vector<Player> team{};

    // Give user instructions and get number of players for input
    std::cout << "How many players do you want to enter?\n";
    int numberOfPlayers{}; std::cin >> numberOfPlayers;

    // Get the player data and add to team
    for (int i = 0; i < numberOfPlayers; ++i) {
        std::cout << "\n\nEnter player data << " << i + 1 << "  One at a line : First name, name, age, score:\n";
        Player player;
        std::cin >> player;
        team.push_back(player);
    }

    // Show complete team:
    std::cout << "\n\nTeam:\n";
    for (const Player& p : team)
        std::cout << p << '\n';
}

Since you did not state your requirements very clearly, I cannot answer further. But you should have understood the basics now and can add further structs and arrays as needed.

Happy coding